Memantine treatment improves opioid-induced hyperalgesia symptoms: randomize clinical trial

Opioid-induced hyperalgesia (OIH) is a condition in which prolonged opioid use paradoxically increases sensitivity to noxious stimuli, resulting in heightened discomfort and diminished tolerance. This study aimed to investigate the clinical effects of Memantine in managing OIH symptoms in opioid-dependent patients. A randomized clinical trial involving 36 opioid-addicted patients diagnosed with opioid-induced hyperalgesia (OIH) was conducted between January and June 2022. Participants were randomly assigned to one of two groups: an intervention group receiving 10 mg/day of memantine, and a control group receiving placebo. The Cold Pressure Test (CPT) and Visual Analog Scale (VAS) were utilized to assess pain tolerance and intensity, respectively. The memantine group showed significantly increased cold pain tolerance at two and four weeks post-intervention (p = 0.005 and p < 0.001) and a significant reduction in pain intensity at two week (p = 0.001), though not at four weeks (p = 0.4536). Repeated measures ANOVA indicated significant within-subject effects of time for both CPT (F = 41.694, p = 0.001, η² = 0.558) and VAS (F = 69.065, p = 0.001, η² = 0.677), while between-group and interaction effects were not significant. This study offers preliminary support for the potential efficacy of 10 mg/day memantine in alleviating OIH symptoms, warranting further investigation to confirm these findings.Trial registration IRCT registration number IRCT20211112053045N1. Registration date 07/12/2021. IRCT URL https//irct.behdasht.gov.ir/trial/60,058. Ethical code IR.ZUMS.REC.1400.26.